The invention relates to a current interrupter, with a contact element between the two connecting parts for its electrical connection and with an auxiliary drive for separating the two connecting parts.
A current interrupter of this kind is known from DE 44 02 994 A1. The contact element, for example, is designed as a surrounding spring basket and also assumes the function of keeping the two connecting parts in an operating position. This results in a connection between the two connecting parts that is difficult to access mechanically. This also allows the danger to persist during manufacturing that the two connecting parts will not be entirely placed 100% in their most effective position. The result is that the function of the current interrupter may not be guaranteed in all cases. The function depends on the efficacy of the auxiliary drive.
In DE 44 02 994 A1, the auxiliary drive is provided by a propellant charge that is ignited (if necessary) and generates a specific amount of gas. Since it is an explosive body, the quantity of explosive is measured exactly and is as small as possible. The quantity is set for the case in which the two connecting parts are located exactly in the active position. If this is not the case, the gas quantity generated may not suffice to reliably separate the other connecting parts from one another. On the other hand, the quantity of explosive cannot be made overly large, since if the two connecting parts are in their proper effective position, this leads to an excessive acceleration of the two contact parts, which in turn is a dangerous situation.
The possibility of omitting the contact part while ensuring both the function of the electrical junction and the retaining force at the location of the electrical backward snap connection with the aid of a (press) fit, does not achieve the object of the present invention. The fit depends on the manufacturing tolerances of the contact surfaces on the one hand and the curve of the pressing force as the two connecting parts are being fitted together, on the other hand. These influential parameters are problematic during the process and result in considerable manufacturing expense, since the pressing force must be guided during the pressing process, for example. Simultaneously, as a result of increased manufacturing cost, where the two connecting parts join the tolerance between the two connecting parts must be kept small.
The object of the invention is to provide a current interrupter which, from a manufacturing standpoint, functions in a safe, reliable and simple manner.
This and other objects and advantages are achieved by the current interrupter, in which the spatial separation of the electrical junction and the location where the retaining force is applied also offers the possibility of adjusting this retaining force independently of the electrical connection. It is then possible not to initially apply the retaining force during manufacture, for example, and to fit the two connecting parts together in a simple loose manner. The electrical junction is then ensured. It is only after manufacture is complete, and it is possible to separate the two connecting parts from one another at any time, that the retaining force is applied by suitable means. This can be accomplished by welding the two connecting parts together, for example.
The possibility of simply separating the two connecting parts from one another, during manufacture for example, and then fitting them together again is achieved most simply where the contact element (as is known) is a circumferential spring basket. However, the dimensions must be adapted to the transverse force so that this transverse force not only produces a good electrical contact, but does not produce a frictional connection between the two connecting parts.
In contrast to the possibility of applying the retaining force by welding the two connecting parts, an advantageous design of the current interrupter is obtained if the retaining force is applied by a housing that is closed around the two connecting elements after the electrical connection is made. Such a housing (advantageously made of plastic) is simple to manufacture and can be accomplished safely and reliably as far as the design features are concerned. The housing can be designed in various ways.
In a first embodiment of the present invention, the housing can be adapted to the external shape of the connecting parts so that it can be closed only when the two connecting parts are in their effective positions.
In a second embodiment of the present invention, the housing can also be provided with breaking elements that produce the desired retaining force. These breaking elements, for example, can be placed in the path of movement of one connecting part. When the auxiliary drive is triggered, the breaking elements initially prevent the movement of the two connecting parts relative to one another. Furthermore, it is only when the auxiliary drive is fully operational that the retaining force exceeds the driving force produced by it. The breaking elements then abruptly allow the movement of one of the two connecting parts. The momentum that is then present will reliably accelerate the movable contact part out of the fixed contact part and break the connection. As a result of the retaining force of the breaking elements, which can be determined by the shape and material of the breaking element, the dynamics of the process of separation of the connecting parts can also be controlled.
In another embodiment of the invention, the housing can also be made in two parts and have a specific breakaway force. The effect of the two housing halves corresponds to that of the breaking elements.
In still another embodiment of the invention, the housing can be designed so that it acts as a cage for the two connecting parts, even when they are pulled apart from one another by the auxiliary drive. As a result, the movement of the connecting parts away from one another is limited and external protection is achieved. By suitable design measures, it is also possible to prevent a backward movement of the connecting parts toward one another and thus to eliminate a renewed contact between the two connecting parts.
The invention will now be described in greater detail with reference to the drawings.